"Fast when you see it, and stop fasting when you see it, and if clouds prevent you from seeing it, then complete the number, and do not fast ahead of Ramadan."  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ حَالَ بَيْنَكُمْ وَبَيْنَهُ سَحَابٌ فَأَكْمِلُوا الْعِدَّةَ وَلاَ تَسْتَقْبِلُوا الشَّهْرَ اسْتِقْبَالاً  

"Fast when you see it, and stop fasting when you see it, and if clouds prevent you from seeing it, then complete the number, and do not fast ahead of Ramadan." (Using translation from Nasāʾī 2129)   

قَالَ رَسُولُ اللهِ ﷺ صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ حَالَ بَيْنَكُمْ وَبَيْنَهُ سَحَابٌ فَكَمِّلُوا الْعِدَّةَ ثَلاثِينَ وَلا تَسْتَقْبِلُوا الشَّهْرَ اسْتِقْبَالًا قَالَ حَاتِمٌ يَعْنِي عِدَّةَ شَعْبَانَ  

[Machine] I entered upon Ikrimah on the day where there was uncertainty about Ramadan, and he was eating. So he said, "Come closer and eat." I said, "Indeed, I am fasting." He said, "By Allah, you will still eat." I said, "Inform me then." He said, "Ibn Abbas narrated to me that the Messenger of Allah ﷺ said, 'Do not fast until you see the month (i.e., the crescent moon), and do not break your fast until you see it. But if it is cloudy or overcast and you cannot see it, then complete the count of thirty days.'"  

دَخَلْتُ عَلَى عِكْرِمَةَ فِي الْيَوْمِ الَّذِي يُشَكُّ فِيهِ مِنْ رَمَضَانَ وَهُوَ يَأْكُلُ فَقَالَ ادْنُ فَكُلْ قُلْتُ إِنِّي صَائِمٌ قَالَ وَاللَّهِ لَتَدْنُوَنَّ قُلْتُ فَحَدِّثْنِي قَالَ حَدَّثَنِي ابْنُ عَبَّاسٍ أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ «لَا تَسْتَقْبِلُوا الشَّهْرَ اسْتِقْبَالًا صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ حَالَ بَيْنَكُمْ وَبَيْنَ مَنْظَرِهِ سَحَابَةٌ أَوْ قَتَرَةٌ فَأَكْمِلُوا الْعِدَّةَ ثَلَاثِينَ يَوْمًا»  

[Machine] The Messenger of Allah ﷺ said, "Fast upon seeing it (the moon) and break your fast upon seeing it. If it is obscured from you, then complete the count (of days) and the month is twenty-nine."  

قَالَ رَسُولُ اللهِ ﷺ «صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ حَالَ دُونَهُ غَيَايَةٌ فَأَكْمِلُوا الْعِدَّةَ وَالشَّهْرُ تِسْعٌ وَعِشْرُونَ»  

[Machine] The Messenger of Allah ﷺ said, "Do not begin the month (of Ramadan) until you see it (the crescent moon), and end the month when you see it (the crescent moon). If it is obscured from you, then complete the count (of days)."  

قَالَ رَسُولُ اللهِ ﷺ «لَا تَسْتَقْبِلُوا الشَّهْرَ صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ حَالَتْ دُونَهُ غَيَايَةٌ فَأَكْمِلُوا الْعِدَّةَ»  

"Fast when you see it, and stop fasting when you see it, and if clouds prevent you from seeing it, then complete the number, and do not fast ahead of Ramadan." (Using translation from Nasāʾī 2129)  

عَنْ رَسُولِ اللهِ ﷺ قَالَ «صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ حَالَ بَيْنَكُمْ وَبَيْنَهُ سَحَابٌ فَكَمِّلُوا الْعِدَّةَ وَلَا تَسْتَقْبِلُوا الشَّهْرَ اسْتِقْبَالًا»  

"صُومُوا لِرُؤْيَتِهِ، وأَفْطرُوا لِرُؤْيَتِه، فإِنْ حَال بَينَكُمْ وَبَينَهُ سَحَابُ فأَكْمِلُوا العِدَّةَ -عِدَّةَ شَعْبَانَ- وَلَا تَسْتَقبِلُوا الشَّهْرَ اسْتِقَبالًا، وَلَا تَصِلُوا رَمضَانَ بِيَوم مِن شَعْبَانَ".